The present invention relates generally to data storage disks, and, more specifically, to micro sized versions thereof.
One type of media for the storing of binary bits of computer data is a magnetic disk typically referred to as a hard disk or hard drive. The disk includes a substrate having a suitable magnetic coating for allowing data to be written thereto and read therefrom in a conventional fashion using a suitable read/write access head. Advances in disk design are being continually made for storing ever increasing amounts of data in smaller and smaller disks.
More specifically, standard form factors are known in the industry which indicate the relative size of data storage disks. Common disk form factors include in decreasing size 5.25 in (14.6 cm), 3.5 in (10.0 cm), 2.5 in (7.3 cm), 1.8 in (5.0 cm), and 1.3 in (3.7 cm). The 14.6 cm form factor is defined by a rectangle 14.6 cm by 20 cm having an area of 292 cm.sup.2. Each successive form factor has half the area of the previous form factor and is obtained by defining a rectangle having a narrow side being one half the long side of the next larger form factor rectangle. Form factors have been continuing to decrease due to the increase in magnetic storage density being developed.
In order to access data storage sectors on the disk, both the access head and the disk are suitably set into motion, with the disk being typically rotated at a suitable rotational velocity. A typical disk drive motor is mounted to the center of the disk for suitably spinning the disk for allowing access to the various sectors thereof.
In a separate development, various types of micromechanical systems (MEMS) such as variable reluctance magnetic micromotors are being fabricated using high aspect ratio lithographic techniques and electroplating processes to form the components thereof. A rotor having one set of poles is assembled to a stator having another set of poles for forming the micromotor. The stator poles include a core formed of a high permeability magnetic material such as nickel-iron around which is formed a conducting coil such as copper. The stator and a stationary support pin for the rotor may be formed using polyimide as a dielectric in a multilevel fabrication process using suitable lithographic masks to define the required components and conventional metal deposition such as electroplating for forming the magnetic core, the conducting coils, and the rotor support pin. The rotor and its poles can be separately fabricated using lithographic and electroplating techniques in a conventional manner, or the rotor and the stator can be fabricated together on one substrate, with the rotor being released using a suitable lift off technique. The assembled micromotor requires no permanent magnets to produce a torque moment, although they may be used in other embodiments. The stator coils are arranged in one or more sets, and phases are excited individually or in pairs to produce torque for rotor rotation. When a phase coil is excited, the nearest rotor poles adjacent to the excited stator poles are attracted to the stator poles. The rotor then rotates to align the rotor poles with the excited stator poles, at which time the excited phase is cut off, and the next phase is then excited to maintain continuous rotation of the rotor by sequentially exciting the stator poles.
In order to further reduce the size of data storage disks, it is desirable to integrate therewith a suitable micromotor for creating data storage microfiles.